In recent years, alternatives to the standard keyboard for communicating with computers have generated a lot of interest. For example, touch screen systems have been developed that permit users to touch an area of a special display screen, which signals the computer to perform a programmed function. The mouse has also grown in popularity with the general acceptance of WINDOWS.TM., and the like, among personal computer users. And voice recognition systems have also gained popularity, however, such systems have not yet been perfected.
Although these alternatives exist, no viable, complete replacement for the standard keyboard has been developed, with one exception, the chord keyboard. In other words, standard keyboards are still used with systems that have touch screens and/or mouses.
Touch screens cannot replace the standard keyboard because it is difficult, for example, to perform word processing functions using a touch screen without a standard keyboard for typing. Similarly, the mouse cannot replace the standard keyboard to perform word processing functions. Although voice recognition systems could replace the standard keyboard, such systems still cannot provide the advantages of the present invention described below.
In contrast, the chord keyboard provides an alternative method of inputting information and commands to a computer using fewer keys than the number of keys included in the standard keyboard. This is accomplishing by assigning characters and functions associated with a single key on the standard keyboard to a single key or group of keys included in the chord keyboard. For example, a user enters the letter "a" using a standard keyboard by merely pressing the key marked with the letter "A" on the keyboard. Using a chord keyboard, however, the user might enter the letter "a" by pressing a "chord", that is, a single key or a combination (or group) of keys simultaneously. Thus, with chord keyboards users can communicate commands and enter information (e.g., characters, numbers, etc.) into a computer in a manner similar to that used with standard keyboards.
Examples of chord keyboard systems are illustrated in U.S. Pat. Nos 4,360,892; 4,442,506; 4,833,446; 5,087,910; and 4,727,478. U.S. Pat. No. 4,727,478 discloses a device for connecting multiple chord keyboards to a single computer. This patent also specifies that each of the chord keyboards is a "portable word processor described in U.S. Pat. No. 4,360,892" (col. 3, lines 7-8).
U.S. Pat. No. 4,360,892 discloses a portable word processor of the type illustrated in FIG. 2 of U.S. Pat. No. 4,727,478. The portable word processor includes a microprocessor. Thus, U.S. Pat. No. 4,727,478 discloses a system where multiple chord keyboards, each containing its own microprocessor, are connected to a host computer. However, each chord keyboard is connected to a separate connector. Thus, to connect four chord keyboards to the host computer, four separate connectors would be required. Additionally, this configuration does not permit one user using a chord keyboard to monitor and, if necessary, to override commands and or information being input to the host computer by another user on a different chord keyboard.
U.S. Pat. No. 5,136,694 discloses a device for facilitating communication between two keyboards and a single processor. U.S. Pat. No. 5,136,694 discloses a computer (10) having an internal keyboard (11). An internal keyboard processor (14) monitors signals from a system control processor (28), a connector (15), and internal keyboard keys (12) in order to facilitate transfers between the system control processor (28) and the internal keyboard (11), as well as transfers between the system control processor (28) and an external keyboard (21). In summary, the internal keyboard has an internal processor that controls input to a computer from another external keyboard. The external keyboard is thus connected to the computer via the processor of the internal keyboard. This device is thus limited to the internal keyboard and a single external keyboard. In other words, without the aid of the present invention discussed below, another chord or standard format keyboard cannot be connected to the internal or external keyboard.
Accordingly, these prior art chord keyboard systems, as well as the standard keyboard, share a significant disadvantage. They do not permit the user to connect multiple keyboards (chord or standard format) to a computer using only the keyboard port of the computer. Connecting multiple keyboards (chord or standard format) to a single keyboard port has many applications, some of which will be described below with reference to the preferred embodiment of the present invention. Other applications will be apparent to one skilled in the art given the description of the preferred embodiment and the example applications of the present invention.